The present invention relates to coaxial cable connectors used in communication systems. More particularly, the present invention relates to improved methods and apparatuses for connecting a coaxial cable to a bulk head.
One of the most commonly used transmission lines in the communication industry is the coaxial cable. A coaxial cable is an electrically conducting transmission line configured for carrying signals to and from different types of circuits. More specifically, coaxial cables are configured to have an inner conductor and outer conductor, which are separated by a dielectric insulator and externally covered by an outer insulator. Generally, the inner conductor is configured for carrying the signal and the outer conductor is configured for shielding the inner conductor. For example, the outer conductor prevents energy from radiating from the inner conductor and blocks the pickup of external signals that might interfere with the reception and/or transmission of the signal carried by the inner conductor (e.g. interference).
Because the coaxial cable can prevent interference, it is commonly used in communication systems such as radio, TV, telephony, data and information destined for microwave transmission. In one specific application, the coaxial cable is used to carry signals between an antenna and a transmitter and/or a receiver. Referring initially to FIG. 1, an exemplary communication system 10 that uses a coaxial cable to connect an antenna to a transmitter/receiver is shown. Communication system 10 typically includes an antenna 12 (or group of antennas) that is structurally disposed on a tower 14. By way of example, the antenna 12 may be a xe2x80x9cwhipxe2x80x9d type antenna, a FM antenna, a microwave type antenna, or a panel type antenna. The antenna 12 is operatively coupled to a coaxial cable 16 that runs down the tower 14 to a transmitter and/or receiver (not shown) housed in a transmitter/receiver station 18.
Furthermore, as the coaxial cable 16 enters the transmitter/receiver station 18, it is typically coupled to a bulkhead (not shown), which is designed to support the coaxial cable 16. In some instances, the bulkhead may also be referred to as an entry port. The bulkhead may be configured to be a single point of entry that may be common to many coaxial cables that originate from multiple antennas on the tower (or towers) or it may be configured to support a single coaxial cable. By way of example, there may be as many as twenty antennas on one tower, and as many as sixteen cables (or more) coupled to the bulk head (or entry port) at one time. Following connection to the bulkhead, the coaxial cable is further connected to a specific transmitter or receiver inside the transmitter/station.
When using coaxial cables, especially in communication systems, it is important to use connectors that connect the outer conductor of the coaxial cable to ground. Grounding the outer conductor further helps to dissipate interference from other signals. Therefore, the coaxial cable is typically coupled to a grounded bulkhead. For the most part, the grounded bulk head is formed from a highly conductive material such as brass or copper and coupled to a ground strip that is further coupled to a grounding system (shown in FIG. 1 as grounding system 20). The grounding system, which is typically part of the transmitter/receiver equipment, may be useful for addressing issues associated with lightning strikes. Grounding systems are well known in the art and for the sake of brevity will not be discussed in detail here.
Presently, a wide variety of coaxial connectors have been provided for connecting a coaxial cable to a bulkhead. In a typical coaxial connector, the coaxial cable is cut in half (in a direction perpendicular to the cable axis), the exposed cable ends are stripped of insulation and the bare outer conductor is inserted into a pair of coaxial connectors where they can be secured to each of the coaxial connectors. More specifically, a collar is secured to each of the stripped ends and locked in place between a locking nut and each of the coaxial connectors. The pair of coaxial connectors are then coupled to the bulkhead.
Referring to FIGS. 2 and 3, a typical coaxial connector system 50 is shown. The coaxial connector system 50 includes a cut coaxial cable 56. The cut coaxial cable 56 is arranged to include an inner conductor 44, an outer conductor 46, an inner insulator 48 (i.e., foam, plastic coil separator, etc.) disposed between the inner and the outer conductor (44, 46), and an outer insulator 49 disposed around the outer conductor 46. Further, the coaxial connector system 50 includes a pair of cable couplers 52 that are coupled to each of the stripped ends 54 of the cut coaxial cable 56. The cable couplers 52 are coupled to the stripped ends 54 by securing a collar 58 around the stripped ends 54 of coaxial cable 56, and thereafter locking the collar 58 between a locking nut 60 and the cable coupler 52.
The cable couplers 52 are formed from a conductive material, and in electrical contact with the outer conductor 46 when secured to the stripped ends 54. Furthermore, a conductive pin 62 is disposed between the inner conductors 44 of the cut coaxial cable 56, in order to electrically connect the broken inner conductor circuit. Following the coupling of the cable couplers to the cut coaxial cable 56, the cable couplers 52 are disposed together and fastened to a grounded bulk head 64. In most instances, the fastening of the cable couplers 52 to the grounded bulkhead 64 is implemented with a plurality of bolts 66.
One problem that has been encountered with the coaxial connector system has been that the coaxial cable is cut in half. As is well known to those skilled in the art, the ability of the coaxial cable to carry a signal is reduced with every cut or break. By way of example, a cut may produce signal reflections that weaken the signal as it is transmitted through the coaxial cable. Signal reflections make it difficult to obtain maximum power transfer through the coaxial cable. Additionally, the cut makes it difficult to achieve proper contact between the conductors of the coaxial cable. Poor connection between mating conductors also leads to weakened signal transmissions.
Furthermore, by cutting the coaxial cable in half, the connection has to be waterproofed to ensure that moisture does not adversely impact the connection. For example, signal loss tends to occur when moisture saturates the conductive path of the conductors. Moisture also tends to corrode the conductors. Referring back to FIG. 2 and 3, the prior art overcomes these disadvantages by disposing a shrink wrap tube 68 over the locking nut 60 and the unstripped portion of the cut coaxial cable 56, and providing an o-ring 70 between the pair of cable couplers 52. Although FIG. 2 and 3 show the shrink wrap tube extending only partially over the cable coupler 52, it should be understood that the shrink wrap tube 68 may be configured with varying lengths and may even extend to the flanged portion of the cable coupler 52. For the most part, the shrink wrap tube 68 prevents the introduction of moisture at the locking nut/coaxial cable interface and the o-ring 70 prevents the introduction of moisture at the cable coupler/cable coupler interface. However, the additions of the shrink wrap tube and the o-ring further increase the complexity and cost of the connection and may loose their sealing ability over a period of time.
Further still, the coaxial connector system is complex, heavy and difficult to handle. The amount of parts (one for each cut end), e.g., cable coupler, collar, locking nut, conductive pin, o-ring, increases the coaxial connector system assembly time and makes it difficult to install. In fact, it typically takes two people to install the coaxial cable and coaxial connectors to the bulkhead. Correspondingly, the use of complex parts and increased man hours lead to increased costs.
In view of the foregoing, there are desired improved methods and apparatuses for electrically and mechanically coupling a coaxial cable to a bulk head. Additionally, there are desired improved methods and apparatuses for providing a substantially weatherproof connection between coaxial cable and a bulkhead. Also, there are desired improved methods and apparatuses that reduce the costs associated with coupling a coaxial cable to a bulkhead.
The invention relates, in one embodiment, to a connector assembly for coupling a continuous length of coaxial cable to a bulkhead. The coaxial cable includes an insulation layer disposed around an outer conductor. The connector assembly includes a first conductive mounting member having an inner peripheral surface that is configured to mate with an outer peripheral surface of the outer conductor for a segment of the continuous length of the coaxial cable. The first conductive mounting member also includes a first bulkhead mating portion that is configured to mate with the bulkhead. The connector assembly further includes a fastener that is configured to couple the first conductive mounting member to the outer conductor of the segment of the continuous length of the coaxial cable, wherein the continuous length of the coaxial cable is uninterrupted within the connector assembly.
The invention relates, in another embodiment, to a connector system for coupling a coaxial cable to a surface. The connector system includes a grounded bulk head. The connector system further includes a continuous length of coaxial cable. The continuous length of coaxial cable includes an insulator layer disposed around an outer conductor. The connector system also includes a conductive sleeve coupled to the continuous length of coaxial cable. The conductive sleeve being configured to mate with the outer peripheral surface of the outer conductor of a segment of the continuous length of coaxial cable. The conductive sleeve further being coupled to the grounded bulk head.
The invention relates, in another embodiment, to a method of coupling an outer conductor of a continuous length of coaxial cable to a grounded bulk head. The coaxial cable includes an insulator layer disposed around the outer conductor. The method includes removing a portion if the insulator layer from the continuous length of coaxial cable, and exposing a segment of the outer conductor of the continuous length of coaxial cable. The method further includes coupling a conductive sleeve around the segment of the outer conductor of the continuous length of coaxial cable. The method additionally includes coupling the conductive sleeve to the grounded bulk head, wherein the conductive sleeve mechanically and electrically couples the outer conductor of the continuous length of coaxial cable to the grounded bulk head and wherein the segment of the outer conductor is uninterrupted within the conductive sleeve.